Choosing a myopia-control strategy in a young patient with moderate myopia and significant astigmatism

Clinical presentation 

An 11-year-old East Asian young person attended with their family to discuss options for myopia management. The child had bilateral myopia with significant astigmatism. They did not like wearing myopia control spectacles, which they had tried in the past.

Examination 

Distance visual acuity 

• RE: −0.10 logMAR
• LE: −0.10 logMAR 

Refraction 

• RE: −2.00 / −2.00 D (SE −3.00 D)
• LE: −2.25 / −1.75 D (SE −3.13 D) 

Axial length 

• RE: 23.94 mm
• LE: 24.16 mm

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Question A :

Considering the advantages and disadvantages of myopia-control spectacle lenses, dual-focus soft contact lenses, orthokeratology and low-concentration atropine and taking into account the child's age, low/moderate myopia, significant astigmatism, treatment burden, safety and lifestyle, the decision was made to commence 0.01% atropine monotherapy.

Question B :

Consider axial-length change in relation to the child's age and ethnicity, and compare observed elongation with expected growth in an untreated myopic child.

You may find it useful to use a publicly available axial-elongation calculator based on the age- and ethnicity-specific model of Brennan et al. (2024), https://onlinelibrary.wiley.com/doi/10.1097/OPX.0000000000002176

For an 11-year-old East Asian child who has untreated myopia, a mean annual axial elongation rate of 0.32mm is expected, with a prediction interval of 0.20 to 0.52mm

Follow-up

After 8 months, axial length was:

• RE: 24.00 mm (extrapolated axial elongation over 12 months: 0.09mm)
• LE: 24.18 mm (extrapolated axial elongation over 12 months: 0.03mm)

After 15 months:

• RE: 24.09 mm (axial elongation over past 7 months: 0.09mm; extrapolated 12-month elongation rate: 0.15mm)
• LE: 24.30 mm (axial elongation over past 7 months: 0.12mm; extrapolated 12-month elongation rate: 0.21mm)

At the 8- and 15-month visits, treatment with atropine 0.01% appeared to have a good to excellent effect on axial elongation.

At 21 months, axial length was:

• RE: 24.06 mm (no increase)
• LE: 24.34 mm (0.04mm increase since the 15-month visit 6 months earlier, with 12 months equivalent of 0.08mm).

For a 12-year-old East Asian child (second year of treatment in this case) with untreated myopia, a mean annual axial elongation rate of 0.28mm is expected, with a prediction interval of 0.17 to 0.45mm. Here, stable axial length in the right eye and minimal elongation in the left eye indicate excellent treatment success.

At 27months:

• The family opted to add defocus spectacles to the existing 0.01% atropine treatment.

At 33 months:

• RE: axial length was 24.15 mm
• LE: 24.41 mm (elongation 21-month visit in your practice, i.e. over past 12 months: right 0.09, left 0.07mm).

Key learning points

• Myopia-control treatment should be individualised according to age, refractive error, astigmatism, lifestyle and treatment burden.
• Significant astigmatism may be an important consideration when selecting an optical treatment.
• Axial length provides an important measure of treatment response and should be interpreted in relation to age and ethnicity.
• Treatment can be adapted over time: in this case, 0.01% atropine monotherapy was subsequently combined with defocus lenses. Families may follow the advice of different practitioners simultaneously to give their child the best possible myopia control outcome. Combining a pharmacological and an optical treatment option augments treatment effect.

Take-home message

Low-concentration atropine is a suitable first-line myopia control option, with longitudinal axial length monitoring allowing treatment to be continued or intensified according to the individual response.